1. Field of the Invention
The present invention relates to measuring tools and to handloading ammunition. More specifically, the present invention relates to a handheld gauge tool that allows a user handloading a firearm bullet to measure the tolerances of a primer pocket without the use of a caliper.
Handloading ammunition has several benefits for the outdoorsman and enthusiast. First, handloading greatly reduces the cost per bullet, once the necessary equipment has been purchased and its investment has been recouped. Secondly, handloading can be used to make more precisely loaded bullets with closer tolerances, which can improve accuracy of the bullet exiting the firearm. Thirdly, the spent brass after a round at the shooting range can be reused and recycled into new bullets, whereby waste is reduced and material usage is reduced. These benefits make handloading a popular activity for some, and particularly to those who enjoy shooting, hunting, and for those who are required to maintain their shooting skills for a profession.
Firearm bullet s generally comprise a bullet projectile, which is supported within a brass case filled with a propellant. The bullet is supported along one end of the case and a primer is positioned at the opposite end. The primer is struck and used to ignite the propellant, whereby the pressure created ejects the bullet from the barrel of the firearm and ejects the empty casing from the ejection port. This configuration is well known in the art of bullets and firearms, and serves as a reliable manner to fire a bullet projectile from the barrel of a firearm.
The present invention specifically pertains to positioning the primer within the primer pocket of the brass casing, and furthermore to swaging tools adapted to cold work the casing while handloading. More specifically, the present invention relates to ensuring proper dimensions are maintained in the primer pocket while handloading, whereby that the primer can be properly seated with the correct tolerances. Primers are typically inserted cautiously but with sufficient force so as to fully seat the primer into a primer pocket. If the pocket is smaller in diameter than the primer, the primer can potentially be crushed and explode during the loading process. If the pocket is shallower than the height of the primer, the primer will stick out of the pocket when positioned therein. This can result in a “slam” fire in which the round lights off as soon as it's chambered. This can also cause the firearm to explode. The potential therefore exists to injure or kill the user and surrounding bystanders if the handloading of the bullet is conducted properly and to correct tolerances.
The present invention comprises a measurement gauge that is sized such that the tool can quickly be deployed and used to determine the appropriate dimensions of a primer pocket without reading indicia. The tool comprises one or more elongated members, each member having a first and a second measuring end. The first end has a specific diameter and is used to measure the minimum diameter of the primer pocket. The second end has a second diameter that is used to measure the maximum diameter of the primer pocket. Along the first end is a depth marker that is used to show whether the depth of the primer pocket is within tolerance when the first end is completely disposed within the primer pocket interior. Primer pockets have specific sizes and allowable tolerances for specific style firearms (i.e. specific primer sizes), therefore a gauge tool is contemplated for each style and size range. Overall, the tool provides a quick dimension measuring device for a user handloading bullets to ensure the proper primer pocket dimensions are within allowable tolerances for the given primer size.
2. Description of the Prior Art
Devices have been disclosed in the prior art that relate to ammunition primer pockets. These include devices that have been patented and published in patent application publications. These devices generally relate to primer loading devices and devices generally for gauging an article of ammunition. The following is a list of devices deemed most relevant to the present disclosure, which are herein described for the purposes of highlighting and differentiating the unique aspects of the present invention, and further highlighting the drawbacks existing in the prior art.
U.S. Pat. No. 5,025,706 to Markle discloses a controlled depth primer seating tool, which comprises a tool the supports a shell casing and controllably inserts a primer into the primer pocket thereof. A measurement assembly measures the depth of the tool probe seats the primer within the primer pocket and provides a slight pre-load compression of the anvil head. The Markle device, while a useful tool for inserting and seating a primer into the primer pocket while accommodating tolerances, is not adept at measuring the primer pocket and ensuring the pocket is sized adequately to receive the primer without causing damage or improper seating thereof.
Similar to Markle is U.S. Pat. No. 4,222,305 to Lee, which discloses a tool for inserting primers in to primer pockets using a spring biased lever mechanism. While being capable of loading primers into respective primer pockets, the Lee device fails to provide a means to measure the primer pocket for adequate clearance prior to inserting the primer thereinto. The purpose and the function of the Lee and Markle device diverge from that of the present invention, wherein the Lee and Markle devices are representative of insertion tools in the art and the present invention relates to a gauge tool prior to inserting a primer.
Gauge tools in the art include U.S. Pat. No. 2,387,645 to Cook, which discloses a gauging machine having an elongated table, a bullet support member, a reciprocating gauging rod, and a reciprocating head member. The gauging rod is pressed into the bullet and through the table, wherein an abutment member maintains alignment between the gauging rod and the bullet. The Cook device is one that is suitable for use on a workbench, wherein a large assembly is supported and a reciprocating mechanism is deployed as the tool holds the bullet. The present invention contemplates a simpler gauging mechanism, wherein one or more gauge rods are used to measure the tolerances of a primer pocket and quickly determine whether the pocket is too wide, too narrow, too shallow or too deep.
Finally, U.S. Pat. No. 4,608,762 to Varner discloses bullet seating gauge that ensures the bullet is properly seated within the bullet casing such that its maximum girth area engages the rifling of the firearm barrel. An elongated, threaded shaft extends through the base of a bullet casing to move the bullet along the opposing end. The threaded shaft extends through the primer pocket bore and through the interior of the casing. Conversely, the present invention relates to a measurement gage after the primer pocket has been positioned within the primer pocket bore. The gauge of the present invention measures the dimensions of the primer pocket itself prior to insertion of the primer thereinto.
The present invention comprises one or more primer pocket gauge tools that are elongated gauge rods having a first end and a second end, wherein the first end measures the minimum diameter of the primer pocket and the second end measures the maximum diameter of the primer pocket. The primer pockets are designed to accommodate a specifically sized primer therein. Proper fitment of the primer therein is of paramount importance, therefore proper dimensions of the pocket must be ensured prior to loading the primer into the pocket. Along with maximum and minimum diameter verification, the gauge tool of the present invention also measures depth of the primer pocket to ensure the depth is within a given allowable tolerance for the specific primer being loaded. The present invention offers a quick reference tool that does not require measurement or an elaborate measuring apparatus that would otherwise require an investment that must be recouped by the handloading user.
Overall, the present invention substantially diverges in design elements from the prior art, and consequently it is clear that there is a need in the art for an improvement to existing primer pocket gauge tool devices. In this regard the instant invention substantially fulfills these needs.